Magnetic field detection device

ABSTRACT

A magnetic field detection device includes a base, a first yoke, and a magneto-resistive effect element. The first yoke is provided on the base, and includes first and second principal surfaces each extending along a first plane, and a first end surface coupling the first and second principal surfaces. The magneto-resistive effect element is provided on the base, and includes a magnetization free layer disposed at a position overlapped with the first yoke in a first direction along the first plane. The first end surface includes an inverted tapered surface inclined relative to the first plane and extending closer to a center point of the magnetization free layer as being away from the base in a second direction orthogonal to the first plane. A distance from the center point to a first edge is shorter than a distance from the center point to a second edge.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP2017-061634 filed on Mar. 27, 2017, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND

The disclosure relates to a magnetic field detection device that detectsa magnetic field by means of a magnetism detection element.

As a magnetic field detection device that detects an external magneticfield, a magnetic field detection device utilizing a Hall element or amagneto-resistive effect element has been known. For example, referenceis made to International Publication No. WO 2008/146809.

SUMMARY

Incidentally, in recent years, it has been requested to improve aperformance of detecting a magnetic field.

It is desirable to provide a magnetic field detection device having amore superior magnetic field detection performance.

A magnetic field detection device according to an embodiment of thedisclosure includes: a base; a first yoke provided on the base, andincluding a first principal surface that extends along a first plane, asecond principal surface that extends along the first plane, and a firstend surface that couples the first principal surface and the secondprincipal surface; and a magneto-resistive effect element provided onthe base, and including a magnetization free layer that is disposed at aposition overlapped with the first yoke in a first direction along thefirst plane. The first end surface includes an inverted tapered surface.The inverted tapered surface extends closer to a center point of themagnetization free layer as being away from the base in a seconddirection orthogonal to the first plane, and is inclined relative to thefirst plane. A distance from the center point of the magnetization freelayer to a first edge is shorter than a distance from the center pointof the magnetization free layer to a second edge. The first edge is alocation at which the first principal surface and the first end surfaceintersect each other, and the second edge is a location at which thesecond principal surface and the first end surface intersect each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate embodiments and,together with the specification, serve to explain the principles of thedisclosure.

FIG. 1 is a schematic cross-sectional view of an overall configurationof a magnetic field detection device according to one example embodimentof the disclosure.

FIG. 2 is a circuit diagram illustrating an example of a signaldetection circuit to be mounted on the magnetic field detection deviceillustrated in FIG. 1.

FIG. 3 is a schematic cross-sectional view of an overall configurationof a magnetic field detection device according to one example embodimentof the disclosure.

FIG. 4 is a schematic cross-sectional view of a magnetic field detectiondevice according to a first modification example.

FIG. 5 is a schematic cross-sectional view of a magnetic field detectiondevice according to a second modification example.

FIG. 6 is a schematic cross-sectional view of a magnetic field detectiondevice according to a third modification example.

FIG. 7 is a schematic cross-sectional view of a magnetic field detectiondevice according to a fourth modification example.

DETAILED DESCRIPTION

Some embodiments of the disclosure are described below in detail withreference to the accompanying drawings.

It is to be noted that the following description is directed toillustrative examples of the technology and not to be construed aslimiting to the technology. Factors including, without limitation,numerical values, shapes, materials, components, positions of thecomponents, and how the components are coupled to each other areillustrative only and not to be construed as limiting to the technology.Further, elements in the following example embodiments which are notrecited in a most-generic independent claim of the technology areoptional and may be provided on an as-needed basis. The drawings areschematic and are not intended to be drawn to scale. It is to be notedthat the like elements are denoted with the same reference numerals, andany redundant description thereof will not be described in detail. It isto be noted that the description is given in the following order.

1. First Example Embodiment

An example of a magnetic field detection device including a pair of softmagnetic layers and a magnetism detection element disposed therebetween.

2. Second Example Embodiment

An example of a magnetic field detection device including additionalsoft magnetic layers at positions that overlap a pair of soft magneticlayers in a layer-stacking direction.

3. Other Modification Examples 1. First Example Embodiment [OverallConfiguration of Magnetic Field Detection Device 10]

First, a description is given, with reference to FIG. 1, of aconfiguration of a magnetic field detection device 10 according to afirst example embodiment of the disclosure. FIG. 1 is a schematiccross-sectional view of an overall configuration example of the magneticfield detection device 10.

The magnetic field detection device 10 may be a device that detectspresence or absence, direction, and intensity of an external magneticfield reaching itself, and may be mounted on an electronic compass, forexample. Here, a direction of a magnetic field to be detected such asthe external magnetic field, for example, may be substantiallycoincident with an X-axis direction, in one embodiment. The magneticfield detection device 10 may include a soft magnetic layer 1 as a firstyoke, a soft magnetic layer 2 as a second yoke, and a magneto-resistiveeffect (MR) element 3 that exhibits a resistance change depending on adirection and intensity of the external magnetic field, for example.Hereinafter, the magneto-resistive effect element 3 is referred to as anMR element 3. The magnetic field detection device 10 may further includea bottom electrode layer 4 and a top electrode layer 5 that supply asense current to the MR element 3. An insulating layer 6 may be providedbetween the soft magnetic layer 1 and the MR element 3, between the softmagnetic layer 1 and the bottom electrode layer 4, and between the softmagnetic layer 1 and the top electrode layer 5. In addition, theinsulating layer 6 may be provided between the soft magnetic layer 2 andthe MR element 3, between the soft magnetic layer 2 and the bottomelectrode layer 4, and between the soft magnetic layer 2 and the topelectrode layer 5.

The X-axis direction is a specific but non-limiting examplecorresponding to a “first direction” in an embodiment of the disclosure,and a Z-axis direction is a specific but non-limiting examplecorresponding to a “second direction” in an embodiment of thedisclosure. An X-Y plane is a specific but non-limiting examplecorresponding to a “first plane” in an embodiment of the disclosure.Further, as used herein, the Z-axis direction may be sometimes referredto as a thickness direction. Furthermore, the bottom electrode layer 4is a specific but non-limiting example corresponding to a “base” in anembodiment of the disclosure.

[Soft Magnetic Layer 1]

The soft magnetic layer 1 includes a principal surface 11 that extendsalong the X-Y plane, a principal surface 12 that extends along the X-Yplane, and an inclined surface 13 that couples the principal surface 11and the principal surface 12 and is inclined relative to the X-Y plane.The soft magnetic layer 1 may have an overhang shape. The inclinedsurface 13 may be an inverted tapered surface that extends closer to alater-described center point 341 of a later-described magnetization freelayer 34 of the MR element 3 as being toward the top electrode layer 5from the bottom electrode layer 4 as the base. In particular, in thepresent example embodiment, the inclined surface 13 may extend tooverhang the MR element 3. A part of the soft magnetic layer 1 and apart of the MR element 3 (i.e., a part of the magnetization free layer34 described later) may overlap each other in a thickness direction. Theprincipal surface 11 and the inclined surface 13 intersect each other atan edge EG11, and the principal surface 12 and the inclined surface 13intersect each other at an edge EG12. The soft magnetic layer 1 mayinclude, for example, a soft magnetic metal material having highsaturation magnetic flux density, such as a nickel-iron alloy (NiFe).The soft magnetic layer 1 may be disposed at a position overlapped withthe magnetization free layer 34 described later in the X-axis direction.Here, the principal surface 11 is a specific but non-limiting examplecorresponding to a “first principal surface” in an embodiment of thedisclosure, and the principal surface 12 is a specific but non-limitingexample corresponding to a “second principal surface” in an embodimentof the disclosure. The inclined surface 13 is a specific butnon-limiting example corresponding to a “first end surface” in anembodiment of the disclosure. Further, the edge EG11 is a specific butnon-limiting example corresponding to a “first edge” in an embodiment ofthe disclosure, and the edge EG12 is a specific but non-limiting examplecorresponding to a “second edge” in an embodiment of the disclosure.

[Soft Magnetic Layer 2]

The soft magnetic layer 2 includes a principal surface 21 that extendsalong the X-Y plane, a principal surface 22 that extends along the X-Yplane, and an inclined surface 23 that couples the principal surface 21and the principal surface 22 and is inclined relative to the X-Y plane.Similarly to the soft magnetic layer 1, the soft magnetic layer 2 mayhave an overhang shape. The inclined surface 23 may be an invertedtapered surface that extends closer to the later-described center point341 of the later-described magnetization free layer 34 of the MR element3 as being toward the top electrode layer 5 from the bottom electrodelayer 4 as the base. In particular, in the present example embodiment,the inclined surface 23 may extend to overhang the MR element 3. A partof the soft magnetic layer 2 and a part of the MR element 3 (i.e., apart of the magnetization free layer 34 described later) may overlapeach other in the thickness direction. The principal surface 21 and theinclined surface 23 intersect each other at an edge EG21. The principalsurface 22 and the inclined surface 23 intersect each other at an edgeEG22. Similarly to the soft magnetic layer 1, the soft magnetic layer 2may include, for example, a soft magnetic metal material having highsaturation magnetic flux density, such as a nickel-iron alloy (NiFe). Itis to be noted that a constituent material of the soft magnetic layer 1and a constituent material of the soft magnetic layer 2 may besubstantially the same as each other, or may be different from eachother. The soft magnetic layer 2 may be disposed on side opposite to thesoft magnetic layer 1 in the X-axis direction, as viewed from the MRelement 3. Further, the soft magnetic layer 2 may be disposed at aposition overlapped with the magnetization free layer 34 described laterin the X-axis direction. Here, the principal surface 21 is a specificbut non-limiting example corresponding to a “third principal surface” inan embodiment of the disclosure, and the principal surface 22 is aspecific but non-limiting example corresponding to a “fourth principalsurface” in an embodiment of the disclosure. The inclined surface 23 isa specific but non-limiting example corresponding to a “second endsurface” in an embodiment of the disclosure. Further, the edge EG21 is aspecific but non-limiting example corresponding to a “third edge” in anembodiment of the disclosure, and the edge EG22 is a specific butnon-limiting example corresponding to a “fourth edge” in an embodimentof the disclosure.

[MR Element 3]

The MR element 3 may be, for example, a CPP (current perpendicular toplane) MR element having a spin-valve structure in which a plurality offunctional films including a magnetic layer are stacked. A sense currentflows in a layer-stacking direction in which the functional films arestacked inside the MR element 3. In a specific but non-limiting example,as illustrated in FIG. 1, the MR element 3 may include a stacked body inwhich an antiferromagnetic layer 31, a magnetization pinned layer 32, anintermediate layer 33, a magnetization free layer 34, and a protectivelayer 35 are stacked in order. The magnetization pinned layer 32 hasmagnetization pinned in a certain direction. The intermediate layer 33does not exhibit a specific magnetization direction. The magnetizationfree layer 34 has magnetization varying in accordance with an externalmagnetic field. It is to be noted that the antiferromagnetic layer 31,the magnetization pinned layer 32, the intermediate layer 33, themagnetization free layer 34, and the protective layer 35 may each have asingle-layer structure or a multi-layer structure configured by aplurality of layers. In such an MR element, the resistance change mayoccur in accordance with a change in the magnetic flux along a filmplane (X-Y plane) orthogonal to the layer-stacking direction (e.g.,Z-axis direction).

The antiferromagnetic layer 31 may include an antiferromagnetic materialsuch as a platinum-manganese alloy (PtMn) and an iridium-manganese alloy(IrMn). The antiferromagnetic layer 31 is in a state, for example, inwhich a spin magnetic moment in a direction substantially the same as anorientation of the magnetization of the adjacent magnetization pinnedlayer 32 and a spin magnetic moment in a direction directly oppositethereto completely cancel each other. The antiferromagnetic layer 31serves to fix the orientation of the magnetization of the magnetizationpinned layer 32 into a certain direction.

The magnetization pinned layer 32 may include, for example, aferromagnetic material such as cobalt (Co), a cobalt-iron alloy (CoFe),and a cobalt-iron-boron alloy (CoFeB). For example, the magnetizationdirection of the magnetization pinned layer 32 may be coincident withthe X-axis direction, in one embodiment.

In a case where the MR element 3 is a magnetic tunneling junction (MTJ)element, the intermediate layer 33 may be a non-magnetic tunnel barrierlayer including a magnesium oxide (MgO), for example. The intermediatelayer 33 may have a thickness that is thin to the extent that a tunnelcurrent based on quantum mechanics is able to pass therethrough. Thetunnel barrier layer including MgO may be obtained by a process such asa process of oxidizing a thin film including magnesium (Mg) and areactive sputtering process in which sputtering of magnesium isperformed under an oxygen atmosphere, besides a sputtering process thatuses a target including MgO, for example. It is also possible toconfigure the intermediate layer 33 with use of an oxide or a nitride ofeach of aluminum (Al), tantalum (Ta), and hafnium (Hf), besides MgO. Ina case where the MR element 3 is a giant magnetoresistive (GMR) element,for example, the intermediate layer 33 may include a non-magnetichighly-electroconductive material such as copper (Cu), ruthenium (Ru)and gold (Au).

The magnetization free layer 34 may be disposed at a position overlappedwith both of the soft magnetic layer 1 and the soft magnetic layer 2 inthe X-axis direction. The magnetization free layer 34 may be a softferromagnetic layer, and may have, for example, a magnetization easyaxis substantially orthogonal to the orientation of the magnetization ofthe magnetization pinned layer 32. The magnetization free layer 34 mayinclude, for example, a material such as a cobalt-iron alloy (CoFe), anickel-iron alloy (NiFe), and a cobalt-iron-boron alloy (CoFeB). Forexample, the direction of the magnetization easy axis of themagnetization free layer 34 may be coincident with a Y-axis, in oneembodiment.

The protective layer 35 may include, for example, a non-magneticelectroconductive material such as tantalum (Ta).

[Bottom Electrode Layer 4 and Top Electrode Layer 5]

The bottom electrode layer 4 may extend on the X-Y plane to come intocontact with a part (e.g., an undersurface of the antiferromagneticlayer 31) of the MR element 3. The top electrode layer 5 may extend onthe X-Y plane to come into contact with any other part (e.g., a topsurface of the magnetization free layer 34) of the MR element 3. Thebottom electrode layer 4 and the top electrode layer 5 may each include,for example, a non-magnetic highly-electroconductive material such ascopper (Cu) and aluminum (Al).

[Signal Detection Circuit]

The magnetic field detection device 10 may include, for example, asignal detection circuit illustrated in FIG. 2. The signal detectioncircuit may include, for example, a voltage application section 101, theMR element 3, a resistance change detector 102, and a signal processor103. The voltage application section 101 and the resistance changedetector 102 may be coupled to the MR element 3. The signal processor103 may be coupled to the resistance change detector 102.

[Detailed Configuration of Magnetic Field Detection Device 10]

A description is given next of a detailed positional relationshipbetween the soft magnetic layer 1 and the MR element 3 and between thesoft magnetic layer 2 and the MR element 3. Here, a distance from aposition XP1 of the center point 341 of the magnetization free layer 34in the X-axis direction to a position XP2 of the edge EG11 in the X-axisdirection is defined as a distance X11. A distance from the position XP1of the center point 341 to a position XP3 of the edge EG12 in the X-axisdirection is defined as a distance X12. For example, the distance X11may be smaller than the distance X12 in one embodiment. Further, adistance from a position ZP1 of the center point 341 of themagnetization free layer 34 in the Z-axis direction to a position ZP2 ofthe edge EG11 in the Z-axis direction is defined as a distance Z11. Adistance from the position ZP1 of the center point 341 to a position ZP3of the edge EG12 in the Z-axis direction is defined as a distance Z12.For example, the distance Z11 may be smaller than the distance Z12 inone embodiment.

A distance X21 from the position XP1 of the center point 341 to aposition XP4 of the edge EG21 in the X-axis direction may be smallerthan a distance X22 from the position XP1 of the center point 341 to aposition XP5 of the edge EG22 in the X-axis direction. A distance Z21from the position ZP1 of the center point 341 to a position ZP4 of theedge EG21 in the Z-axis direction may be smaller than a distance Z22from the position ZP1 of the center point 341 to a position ZP5 of theedge EG22 in the Z-axis direction. Further, a spacing D1 between theposition XP2 of the edge EG11 in the X-axis direction and the positionXP4 of the edge EG21 in the X-axis direction may be narrower than aspacing D2 between the position XP3 of the edge EG12 in the X-axisdirection and the position XP5 of the edge EG22 in the X-axis direction.

Moreover, for example, a thickness T1 of the soft magnetic layer 1 and athickness T2 of the soft magnetic layer 2 may be substantially equal toeach other in one embodiment. For example, a position of the principalsurface 11 in the Z-axis direction and a position of the principalsurface 21 in the Z-axis direction may be substantially coincident witheach other in one embodiment. A position of the principal surface 12 inthe Z-axis direction and a position of the principal surface 22 in theZ-axis direction may be substantially coincident with each other in oneembodiment.

[Workings and Effects of Magnetic Field Detection Device 10]

In the magnetic field detection device 10, an output corresponding tothe external magnetic field that reaches the magnetic field detectiondevice 10 is obtained by the signal detection circuit illustrated inFIG. 2. In a specific but non-limiting example, the voltage applicationsection 101 applies a predetermined voltage between the bottom electrodelayer 4 and the top electrode layer 5 in the above-described signaldetection circuit to thereby cause a sense current to flow. The sensecurrent corresponds to an electric resistance of the MR element 3 atthat time. The electric resistance of the MR element 3 varies dependingon a magnetization state of the MR element 3, i.e., depending on anorientation of the magnetization of the magnetization free layer 34 withrespect to the orientation of the magnetization of the magnetizationpinned layer 32. The sense current flowing through the MR element 3 isdetected by the resistance change detector 102, and the resistancechange detector 102 outputs a signal to the signal processor 103.Further, a signal generated in the signal processor 103 on the basis ofthe output from the resistance change detector 102 is outputted to theoutside. This makes it possible to obtain, from the signal detectioncircuit, an output corresponding to the external magnetic field thatreaches the magnetic field detection device 10.

In the magnetic field detection device 10 according to the presentexample embodiment, the MR element 3 includes the magnetization freelayer 34 disposed at a position overlapped with the soft magnetic layer1 in the X-axis direction. Here, the distance from the center point 341of the magnetization free layer 34 to the edge EG11 of the soft magneticlayer 1 is set shorter than the distance from the center point 341 tothe edge EG12 of the soft magnetic layer 1. In a specific butnot-limiting example, the distance X11 from the position XP1 of thecenter point 341 in the X-axis direction to the position XP2 of the edgeEG11 in the X-axis direction is set smaller than the distance X12 fromthe position XP1 of the center point 341 in the X-axis direction to theposition XP3 of the edge EG12 in the X-axis direction. Further, thedistance Z11 from the position ZP1 of the center point 341 in the Z-axisdirection to the position ZP2 of the edge EG11 in the Z-axis directionis set smaller than the distance Z12 from the position ZP1 of the centerpoint 341 in the Z-axis direction to the position ZP3 of the edge EG12in the Z-axis direction. Adopting such a configuration enables themagnetic field detection device 10 to efficiently concentrate a magneticflux on the magnetization free layer 34 via the soft magnetic layer 1and the soft magnetic layer 2. As a result, application of an externalmagnetic field along the X-axis direction to the magnetic fielddetection device 10, for example, makes it possible to efficientlyconcentrate the magnetic flux on the magnetization free layer 34. Thus,it is possible for the magnetic field detection device 10 to exert ahigh magnetic field detection performance.

Moreover, the soft magnetic layer 1 and the soft magnetic layer 2 mayeach have an overhang shape; the inclined surface 13 and the inclinedsurface 23 may be each an inverted tapered surface that so extends as tooverhang the MR element 3 as being toward the top electrode layer 5 fromthe bottom electrode layer 4 as the base. Accordingly, uponmanufacturing of the magnetic field detection device 10, the softmagnetic layer 1 and the soft magnetic layer 2 may be formed,respectively, on both adjacent sides of the MR element 3 in the X-axisdirection after stacking of the MR element 3 on the bottom electrodelayer 4 as the base. Thus, it is easier to manufacture the MR element 3than a case of forming the MR element 3 between the soft magnetic layer1 and the soft magnetic layer 2 after formation thereof, for example. Inaddition, it is advantageous to enhance uniformity in a film quality anda thickness of each of layers that configure the MR element 3. Inparticular, a part of the soft magnetic layer 1 is designed to overlap apart of the MR element 3 (i.e., a part of the magnetization free layer34 described later) in the thickness direction. This enables both thedistance from the magnetization free layer 34 to the edge EG11 of thesoft magnetic layer 1 and the distance from the magnetization free layer34 to the edge EG21 of the soft magnetic layer 2 to be shorter.Accordingly, a magnetic flux having higher density reaches themagnetization free layer 34, thus making it possible for the magneticfield detection device 10 to exert a higher magnetic field detectionperformance.

2. Second Example Embodiment

A description is given next of a magnetic field detection device 10Aaccording to a second example embodiment of the disclosure, withreference to FIG. 3. FIG. 3 is a schematic cross-sectional view of anoverall configuration example of the magnetic field detection device10A.

The magnetic field detection device 10A according to the present exampleembodiment has a configuration substantially similar to that of themagnetic field detection device 10 of the foregoing first exampleembodiment, except that a soft magnetic layer 51 and a soft magneticlayer 52 are further provided. Therefore, in the following description,the above-mentioned difference is mainly described, and descriptions ofsubstantially the same components as those of the magnetic fielddetection device 10 in the foregoing first example embodiment areomitted where appropriate.

In a specific but non-limiting example, in the magnetic field detectiondevice 10A, the soft magnetic layer 51 may be disposed at a positionoverlapped with the soft magnetic layer 1 in the Z-axis direction, otherthan a position overlapped with the MR element 3 in the Z-axisdirection, as illustrated in FIG. 3. The soft magnetic layer 51 may bestacked on the top electrode layer 5 with an insulating layer 7 beinginterposed therebetween. In the magnetic field detection device 10A, thesoft magnetic layer 52 may be further disposed at a position overlappedwith the soft magnetic layer 2 in the Z-axis direction, other than aposition overlapped with the MR element 3 in the Z-axis direction. Thesoft magnetic layer 51 and the soft magnetic layer 52 may be positionedopposite to each other in the Z-axis direction, with the MR element 3being interposed therebetween. The soft magnetic layer 52 may beprovided below the bottom electrode layer 4, with an insulating layer 8being interposed therebetween, and may be embedded inside a substrate 9,for example. It is to be noted that, in one embodiment, the MR element 3and the soft magnetic layer 51 may be spaced apart from each other inthe X-axis direction, and the MR element 3 and the soft magnetic layer52 may be spaced apart from each other in the X-axis direction. Further,the soft magnetic layer 51 may be so provided as to be common to twoadjacent MR elements 3, or one soft magnetic layer 51 may be providedfor each MR element 3. The same holds true also for the soft magneticlayer 52.

In this manner, the magnetic field detection device 10A according to thepresent example embodiment may include the soft magnetic layer 51provided obliquely above the MR element 3 and the soft magnetic layer 52provided obliquely below the MR element 3. This makes it possible toconverge the external magnetic field from a direction other than theX-axis direction in which the magnetization free layer 34 exhibits highsensitivity, and thus to guide a magnetic flux having higher density tothe magnetization free layer 34. Thus, it becomes possible for themagnetic field detection device 10A to exert a higher magnetic fielddetection performance than that of the magnetic field detection device10.

3. Other Modification Examples

The disclosure has been described hereinabove referring to someembodiments. However, the disclosure is not limited to such embodiments,and may be modified in a variety of ways. For example, FIGS. 1 and 3each illustrate a case where the soft magnetic layer 1 and the softmagnetic layer 2 have substantially the same shape and the substantiallysame size; however, the soft magnetic layer 1 and the soft magneticlayer 2 may have different shapes and different sizes. Further, in theforegoing example embodiments, the position of the principal surface 11in the Z-axis direction and the position of the principal surface 21 inthe Z-axis direction are set coincident with each other; however, theposition of the principal surface 11 and the position of the principalsurface 21 may be different from each other in an embodiment of thedisclosure. Likewise, in the foregoing example embodiments, the positionof the principal surface 12 in the Z-axis direction and the position ofthe principal surface 22 in the Z-axis direction are set coincident witheach other; however, the position of the principal surface 12 and theposition of the principal surface 22 may be different from each other inthe disclosure. Further, the magnetic field detection device of anembodiment of the disclosure may include only one of the soft magneticlayer 1 and the soft magnetic layer 2.

Further, FIGS. 1 and 3 each illustrate a case where the MR element 3,the soft magnetic layer 1, and the soft magnetic layer 2 havesubstantially the same thickness with one another; however, thedisclosure is not limited thereto. For example, as in a magnetic fielddetection device 10B illustrated in FIG. 4, the thickness of the MRelement 3 may be thinner than each of the thickness T1 of the softmagnetic layer 1 and the thickness T2 of the soft magnetic layer 2. Inan alternative embodiment, the thickness of the MR element 3 may belarger than each of the thickness T1 of the soft magnetic layer 1 andthe thickness T2 of the soft magnetic layer 2, as in a magnetic fielddetection device 10C illustrated in FIG. 5. Further, in the foregoingexample embodiment, the soft magnetic layer 1 has the substantiallyconstant thickness T1, and the soft magnetic layer 2 has thesubstantially constant thickness T2; however, the disclosure is notlimited thereto. For example, as in a magnetic field detection device10D illustrated in FIG. 6, the thickness T1 of the soft magnetic layer 1and the thickness T2 of the soft magnetic layer 2 may each vary in theX-axis direction. In any case, it is sufficient for the magnetizationfree layer 34 to be disposed at a position overlapped with one or bothof the soft magnetic layer 1 and the soft magnetic layer 2 in the X-axisdirection.

The foregoing first example embodiment exemplifies the case where themagnetic field detection device 10 includes one soft magnetic layer 1,one soft magnetic layer 2, and one MR element 3. However, the disclosuremay encompass a case where the magnetic field detection device 10 mayinclude a plurality of soft magnetic layers 1, a plurality of softmagnetic layers 2, and a plurality of MR elements 3. Further, theforegoing second example embodiment exemplifies the case where themagnetic field detection device 10A includes two soft magnetic layers 1,two soft magnetic layers 2, and two MR elements 3. However, thedisclosure may encompass a case where the magnetic field detectiondevice 10A may include one soft magnetic layer 1, one soft magneticlayer 2, and one MR element 3.

The foregoing example embodiments have exemplified and have describedthe inclined surface 13 and the inclined surface 23, respectively, asthe specific but non-limiting example of the “first end surface” in anembodiment of the disclosure and as the specific but non-limitingexample of the “second end surface” in an embodiment of the disclosure.The inclined surface 13 is inclined continuously from the edge EG11 tothe edge EG12. The inclined surface 23 is inclined continuously from theedge EG21 to the edge EG22. However, the “first end surface” in anembodiment of the disclosure is not limited thereto; for example, aninverted tapered surface with only a part thereof being inclinedrelative to the first surface may be adopted. The same holds true alsofor the “second end surface” in an embodiment of the disclosure. In aspecific but non-limiting example, for example, the disclosure mayencompass a case where, as in a magnetic field detection device 10Eillustrated in FIG. 7, an inclined surface 13A that is the invertedtapered surface is included in a part of the “first end surface”extending from the edge EG11 to the edge EG12, and an inclined surface23A that is the inverted tapered surface is included in a part of the“second end surface” extending from the edge EG21 to the edge EG22.

In the magnetic field detection device 10A according to the foregoingsecond example embodiment, the soft magnetic layer 51 may be providedobliquely above the MR element 3, and the soft magnetic layer 52 may beprovided obliquely below the MR element 3; however, the disclosure isnot limited thereto. For example, the soft magnetic layer 52 may beprovided obliquely below the MR element 3 without providing the softmagnetic layer 51. In an alternative embodiment, the soft magnetic layer51 may be provided obliquely above the MR element 3 without providingthe soft magnetic layer 52.

Further, in the magnetic field detection device 10A according to theforegoing second example embodiment, the soft magnetic layer 51 may bedisposed at a position overlapped with the soft magnetic layer 1 in theZ-axis direction, other than a position overlapped with the MR element 3in the Z-axis direction. However, the disclosure is not limited thereto;for example, it is sufficient for the soft magnetic layer 51 to bedisposed at a position other than a position overlapped with the centerpoint 341 (in FIG. 1, etc.) of the magnetization free layer 34 of the MRelement 3 in the Z-axis direction. Accordingly, a part of themagnetization free layer 34 and the soft magnetic layer 51 may overlapeach other in the Z-axis direction. Further, the soft magnetic layer 51may be disposed at a position other than a position overlapped with thesoft magnetic layer 1 in the Z-axis direction. The same holds true alsofor a positional relationship between the soft magnetic layer 52 and theMR element 3 as well as for a positional relationship between the softmagnetic layer 52 and the soft magnetic layer 2.

Descriptions have been given, in the foregoing embodiments, byexemplifying, as the magnetism detection element, the CPP MR elementhaving the spin-valve structure; however, the disclosure is not limitedthereto. For example, a CIP (current in plane) MR element or themagnetic tunneling junction element (MTJ element) may be used as themagnetism detection element. In an alternative embodiment, a sensor mayalso be used, such as a magnetism detection element (e.g., Hall element)having the sensing direction as the X-axis direction, other than the MRelement.

Moreover, the disclosure encompasses any possible combination of some orall of the various embodiments and the modification examples describedherein and incorporated herein.

It is possible to achieve at least the following configurations from theabove-described example embodiments of the disclosure.

(1)

A magnetic field detection device including:

a base;

a first yoke provided on the base, the first yoke including a firstprincipal surface that extends along a first plane, a second principalsurface that extends along the first plane, and a first end surface thatcouples the first principal surface and the second principal surface;and

a magneto-resistive effect element provided on the base, and including amagnetization free layer that is disposed at a position overlapped withthe first yoke in a first direction along the first plane,

the first end surface including an inverted tapered surface, theinverted tapered surface extending closer to a center point of themagnetization free layer as being away from the base in a seconddirection orthogonal to the first plane, and being inclined relative tothe first plane, and

a distance from the center point of the magnetization free layer to afirst edge being shorter than a distance from the center point of themagnetization free layer to a second edge, the first edge being alocation at which the first principal surface and the first end surfaceintersect each other, the second edge being a location at which thesecond principal surface and the first end surface intersect each other.

(2)

The magnetic field detection device according to (1), in which

a first distance between a position of the center point of themagnetization free layer in the first direction and a position of thefirst edge in the first direction is smaller than a second distancebetween the position of the center point of the magnetization free layerin the first direction and a position of the second edge in the firstdirection, and

a third distance between a position of the center point of themagnetization free layer in the second direction and a position of thefirst edge in the second direction is smaller than a fourth distancebetween the position of the center point of the magnetization free layerin the second direction and a position of the second edge in the seconddirection.

(3)

The magnetic field detection device according to (1) or (2), furtherincluding a second yoke disposed at a position that is positioned onside opposite to the first yoke in the first direction as viewed fromthe magneto-resistive effect element, and that is overlapped with themagnetization free layer in the first direction, the second yokeincluding a third principal surface that extends along the first plane,a fourth principal surface that extends along the first plane, and asecond end surface that couples the third principal surface and thefourth principal surface,

the second end surface including an inverted tapered surface, theinverted tapered surface extending closer to the center point of themagnetization free layer as being away from the base, and being inclinedrelative to the first plane, and

a distance from the center point of the magnetization free layer to athird edge being shorter than a distance from the center point of themagnetization free layer to a fourth edge, the third edge being alocation at which the third principal surface and the second end surfaceintersect each other, the fourth edge being a location at which thefourth principal surface and the second end surface intersect eachother.

(4)

The magnetic field detection device according to (3), in which

a fifth distance between a position of the center point of themagnetization free layer in the first direction and a position of thethird edge in the first direction is smaller than a sixth distancebetween the position of the center point of the magnetization free layerin the first direction and a position of the fourth edge in the firstdirection,

a seventh distance between a position of the center point of themagnetization free layer in the second direction and a position of thethird edge in the second direction is smaller than an eighth distancebetween the position of the center point of the magnetization free layerin the second direction and a position of the fourth edge in the seconddirection, and

a first spacing between the position of the first edge in the firstdirection and the position of the third edge in the first direction isnarrower than a second spacing between the position of the second edgein the first direction and the position of the fourth edge in the firstdirection.

(5)

The magnetic field detection device according to (3) or (4), in which athickness of the first yoke and a thickness of the second yoke aresubstantially same as each other.

(6)

The magnetic field detection device according to any one of (3) to (5),in which

a position of the first principal surface in the second direction and aposition of the third principal surface in the second direction aresubstantially coincident with each other, and

a position of the second principal surface in the second direction and aposition of the fourth principal surface in the second direction aresubstantially coincident with each other.

(7)

The magnetic field detection device according to any one of (3) to (6),in which the magnetization free layer is disposed at a positionoverlapped with both of a part of the first yoke and a part of thesecond yoke in the second direction.

(8)

The magnetic field detection device according to any one of (3) to (7),further including a third yoke that is disposed at a position other thana position overlapped with the center point of the magnetization freelayer in the second direction.

(9)

The magnetic field detection device according to (8), in which the thirdyoke is disposed at the position overlapped with the first yoke in thesecond direction.

(10)

The magnetic field detection device according to (9), in which themagneto-resistive effect element and the third yoke are spaced apartfrom each other in the first direction.

(11)

The magnetic field detection device according to any one of (3) to (7),further including a third yoke and a fourth yoke that are each disposedat a position other than a position overlapped with the center point ofthe magnetization free layer in the second direction.

(12)

The magnetic field detection device according to (11), in which

the third yoke is disposed at the position overlapped with the firstyoke in the second direction, and the fourth yoke is disposed at aposition overlapped with the second yoke in the second direction.

(13)

The magnetic field detection device according to (11) or (12), in whichthe third yoke and the fourth yoke are disposed at positions that arepositioned on sides opposite to each other in the second direction, withthe magneto-resistive effect element being interposed therebetween.

(14)

The magnetic field detection device according to any one of (11) to(13), in which

the magneto-resistive effect element and the third yoke are spaced apartfrom each other in the first direction, and

the magneto-resistive effect element and the fourth yoke are spacedapart from each other in the first direction.

(15)

The magnetic field detection device according to any one of (1) to (14),in which the magnetization free layer extends along the first plane.

In the magnetic field detection device according to one embodiment ofthe disclosure, adopting the above-described configuration makes itpossible to effectively increase intensity of a magnetic field to bedetected that reaches the magnetization free layer via the first yoke.

According to the magnetic field detection device of one embodiment ofthe disclosure, it is possible to improve intensity of a magnetic fieldto be detected that acts on the magnetization free layer in themagneto-resistive effect element. Thus, it is possible for the magneticfield detection device according to one embodiment of the disclosure toexert a superior magnetic field detection performance.

Although the disclosure has been described in terms of exemplaryembodiments, it is not limited thereto. It should be appreciated thatvariations may be made in the described embodiments by persons skilledin the art without departing from the scope of the disclosure as definedby the following claims. The limitations in the claims are to beinterpreted broadly based on the language employed in the claims and notlimited to examples described in this specification or during theprosecution of the application, and the examples are to be construed asnon-exclusive. For example, in this disclosure, the term “preferably”,“preferred” or the like is non-exclusive and means “preferably”, but notlimited to. The use of the terms first, second, etc. do not denote anyorder or importance, but rather the terms first, second, etc. are usedto distinguish one element from another. The term “substantially” andits variations are defined as being largely but not necessarily whollywhat is specified as understood by one of ordinary skill in the art. Theterm “about” as used herein can allow for a degree of variability in avalue or range. Moreover, no element or component in this disclosure isintended to be dedicated to the public regardless of whether the elementor component is explicitly recited in the following claims.

What is claimed is:
 1. A magnetic field detection device comprising: abase; a first yoke provided on the base, the first yoke including afirst principal surface that extends along a first plane, a secondprincipal surface that extends along the first plane, and a first endsurface that couples the first principal surface and the secondprincipal surface; and a magneto-resistive effect element provided onthe base, and including a magnetization free layer that is disposed at aposition overlapped with the first yoke in a first direction along thefirst plane, the first end surface including an inverted taperedsurface, the inverted tapered surface extending closer to a center pointof the magnetization free layer as being away from the base in a seconddirection orthogonal to the first plane, and being inclined relative tothe first plane, and a distance from the center point of themagnetization free layer to a first edge being shorter than a distancefrom the center point of the magnetization free layer to a second edge,the first edge being a location at which the first principal surface andthe first end surface intersect each other, the second edge being alocation at which the second principal surface and the first end surfaceintersect each other.
 2. The magnetic field detection device accordingto claim 1, wherein a first distance between a position of the centerpoint of the magnetization free layer in the first direction and aposition of the first edge in the first direction is smaller than asecond distance between the position of the center point of themagnetization free layer in the first direction and a position of thesecond edge in the first direction, and a third distance between aposition of the center point of the magnetization free layer in thesecond direction and a position of the first edge in the seconddirection is smaller than a fourth distance between the position of thecenter point of the magnetization free layer in the second direction anda position of the second edge in the second direction.
 3. The magneticfield detection device according to claim 1, further comprising a secondyoke disposed at a position that is positioned on side opposite to thefirst yoke in the first direction as viewed from the magneto-resistiveeffect element, and that is overlapped with the magnetization free layerin the first direction, the second yoke including a third principalsurface that extends along the first plane, a fourth principal surfacethat extends along the first plane, and a second end surface thatcouples the third principal surface and the fourth principal surface,the second end surface including an inverted tapered surface, theinverted tapered surface extending closer to the center point of themagnetization free layer as being away from the base, and being inclinedrelative to the first plane, and a distance from the center point of themagnetization free layer to a third edge being shorter than a distancefrom the center point of the magnetization free layer to a fourth edge,the third edge being a location at which the third principal surface andthe second end surface intersect each other, the fourth edge being alocation at which the fourth principal surface and the second endsurface intersect each other.
 4. The magnetic field detection deviceaccording to claim 3, wherein a fifth distance between a position of thecenter point of the magnetization free layer in the first direction anda position of the third edge in the first direction is smaller than asixth distance between the position of the center point of themagnetization free layer in the first direction and a position of thefourth edge in the first direction, a seventh distance between aposition of the center point of the magnetization free layer in thesecond direction and a position of the third edge in the seconddirection is smaller than an eighth distance between the position of thecenter point of the magnetization free layer in the second direction anda position of the fourth edge in the second direction, and a firstspacing between a position of the first edge in the first direction andthe position of the third edge in the first direction is narrower than asecond spacing between a position of the second edge in the firstdirection and the position of the fourth edge in the first direction. 5.The magnetic field detection device according to claim 3, wherein athickness of the first yoke and a thickness of the second yoke aresubstantially same as each other.
 6. The magnetic field detection deviceaccording to claim 3, wherein a position of the first principal surfacein the second direction and a position of the third principal surface inthe second direction are substantially coincident with each other, and aposition of the second principal surface in the second direction and aposition of the fourth principal surface in the second direction aresubstantially coincident with each other.
 7. The magnetic fielddetection device according to claim 3, wherein the magnetization freelayer is disposed at a position overlapped with both of a part of thefirst yoke and a part of the second yoke in the second direction.
 8. Themagnetic field detection device according to claim 3, further comprisinga third yoke that is disposed at a position other than a positionoverlapped with the center point of the magnetization free layer in thesecond direction.
 9. The magnetic field detection device according toclaim 8, wherein the third yoke is disposed at the position overlappedwith the first yoke in the second direction.
 10. The magnetic fielddetection device according to claim 9, wherein the magneto-resistiveeffect element and the third yoke are spaced apart from each other inthe first direction.
 11. The magnetic field detection device accordingto claim 3, further comprising a third yoke and a fourth yoke that areeach disposed at a position other than a position overlapped with thecenter point of the magnetization free layer in the second direction.12. The magnetic field detection device according to claim 11, whereinthe third yoke is disposed at the position overlapped with the firstyoke in the second direction, and the fourth yoke is disposed at aposition overlapped with the second yoke in the second direction. 13.The magnetic field detection device according to claim 11, wherein thethird yoke and the fourth yoke are disposed at positions that arepositioned on sides opposite to each other in the second direction, withthe magneto-resistive effect element being interposed therebetween. 14.The magnetic field detection device according to claim 11, wherein themagneto-resistive effect element and the third yoke are spaced apartfrom each other in the first direction, and the magneto-resistive effectelement and the fourth yoke are spaced apart from each other in thefirst direction.
 15. The magnetic field detection device according toclaim 1, wherein the magnetization free layer extends along the firstplane.